This invention relates to polymers of ethylene. In one of its aspects this invention relates to stabilizing polymers of ethylene. In another of its aspects, this invention relates to polymers of ethylene containing a hindered phenolic stabilizer. In still another aspect of the invention it relates to improving the color of polymers of ethylene containing a hindered phenolic stabilizer when the polymers are processed at high temperatures.
Stabilizing polymers of ethylene using hindered phenolic compounds has been recognized to cause the problem of producing color in the stabilized polymers upon further high temperature treatment of these polymers. It has been conjectured that a possible source of the color can be the combination of catalyst residues and hindered phenolic stabilizers present in the finished resin. Whatever other factors influence the production of color, the presence of hindered phenolic stabilizer is recognized as contributory to the problem. It has now been found that coloration can be reduced or even eliminated while treating stabilized polymers of ethylene at temperatures of 500.degree. F. or higher.
It is therefore an object of this invention to provide a method for decreasing or eliminating the development of color in stabilized polymers of ethylene upon treating the stabilized polymers at elevated temperature. It is another object of this invention to provide stabilized polymers of ethylene that are resistant to increasing of coloration upon being treated at elevated temperature.
Other aspects, objects and the various advantages of this invention will become apparent upon reading this specification and the appended claims.